Sleep Cycles explained: How they work and how to use them
Surely you know the days when the alarm rings at the exact moment when you are just dreaming. Too often these are the days when we don’t seem to wake up all day. This is due to our sleep cycles. But those who know their mode of operation can use them effectively for their own purposes.
Most of us know that. We are in the middle of deep sleep, just dreaming and suddenly the alarm rings. It often takes us a few seconds to realize that the alarm clock isn’t part of our dream but calls us back to reality.
So awkwardly torn from sleep, we usually think in these moments, that the day actually could not get worse. Of course, you already know that you should avoid talking such things to yourself (self-fulfilling prophecy). But that there are times that are either more or less suitable for waking up, really has a understandable reason.
The human sleep cycles explained
When we sleep, our body goes through different phases, which are differentiated by the depth of our sleep. During a cycle that lasts about 90 minutes, we go through phases of falling asleep, deep sleep, and REM sleep, in which we dream, for example. Once the cycle has been completed, it starts again.
After a period of falling asleep, in which the movement of our body and also the activity of our brain reduces, we reach – after about 60 minutes – in the so-called REM sleep. This phase, which lasts only about 20 minutes, is characterized by our rapid eye movements throughout and also the phase in which we dream.
The REM sleep phase is followed by about 5 minutes of normal sleep before the cycle begins again. The phases of deep sleep are getting shorter and shorter from cycle to cycle.
Depending on how long you sleep at night, you can expect more or less complete sleep cycles. For a sleep duration of 6 hours, for example, it would be exactly 4 cycles (4x 90 minutes = 6 hours)
Our sleep cycles in everyday life
Now that you know how your body’s sleep cycles work, you may already be able to imagine what happens when the alarm goes off. Let’s say you go to bed at 11pm and your alarm rings at 6:30 in the morning. If you need about 15 minutes to fall asleep, you’ll get 7 hours and 15 minutes of sleep before your alarm goes off. What initially sounds like enough sleep turns out to be problematic with regard to the sleep phases:
At about 5.15 am (after 6 hours), your body had completed the fourth sleep cycle. When your alarm rings, you’re in the 75th minute of a new cycle, exactly in REM sleep. So with a high degree of probability, you will be torn exactly out of your dreams and the sleep phase will be stopped before completion. The result: we feel as if we have been hit by a truck.
How we can use sleep cycles
Surely you can already imagine it. The trick is to avoid awakening during REM sleep, and at best go through every sleep cycle to the end.
What may sound complicated at first glance, is ultimately relatively simple. Just choose a sleep duration that is divisible by 90 minutes (1.5 hours). Healthy sleep lengths would thus be 6 hours, 7.5 hours, 9 hours and so on. If you think about how long it takes you to fall asleep, you can easy calculate your perfect bed time.
Some example: You have to get up at 7:00 am and want to sleep for 7.5 hours. That means you should go to bed at 11:15 pm. You’ll see that when you wake up, you’ll feel a lot fitter when your sleep cycle is complete and you’re not torn from sleep. So give it a try.
In a nutshell
As we sleep, we go through several sleep cycles made up of periods of light and deep sleep. Each of these sleep cycles takes about 90 minutes. If we wake up before completing a cycle, for example in the middle of deep sleep or REM sleep, we feel uncomfortable and uneaten.
By adjusting our sleep patterns to the duration of the sleep cycles, we can significantly increase our sleep and wake-up quality and thus start the day with more energy.